[Glucokinase gene mutation as a causative factor of permanent neonatal diabetes mellitus]

The most frequent type of diabetes in childhood is type 1 diabetes. Thanks to the development of genetic testing, the rare monogenic forms of that disease have been defined. One of them is neonatal diabetes identified within the first 6 months of life and often associated with the mutation in KCNJ11, ABCC8 or insulin gene. A less frequent mutation in the glucokinase gene can cause both permanent neonatal diabetes as well as mild diabetes MODY 2.

A 33-day-old boy admitted to hospital because of hyperglycemia from the first day of life. Treatment with intravenous infusion of insulin since 5 days of life. A child born out of the first pregnancy in the 37th week of gestation, with hypotrophy symptoms. The pregnancy had been complicated by gestational diabetes. Birth weight 2030 g. Insulin and c-peptide level significantly below normal. Immunologic markers of type 1 diabetes were negative. A continuous subcutaneous insulin infusion using a personal insulin pump was begun in the 60th day of life. Irregularities in the economy of carbohydrates were found in the parents. A double mutation in the glucokinase gene in genetic testing explained the cause of neonatal diabetes. The boy had inherited from his parents two different mutations in glucokinase gene: from the mother S384L and from the father T207M. He is a complex heterozygote.

Genetic diagnosis helped determine the cause of neonatal diabetes in the child and MODY 2 diabetes in the parents. Personal insulin pump therapy is the most effective treatment in children during infancy.